Microsilica (silica fume) is a by-product of silicon metal or ferrosilicon industries, is an amorphous silicon dioxide SiO2. This product reacts chemically with the calcium hydroxide in the cement paste which yields a calcium silicate hydrate gel that significantly enhances strength and durability. The super fine microsilica fills the voids between cement particles creating a very dense, less permeable concrete. Physical characteristics: Color: gray or gray white powder Bulk density: 320-700 kg/m3 Chemical composition: Items SiO2 Al2O3 Fe2O3 MgO CaO Na2O Moisture Content 75-98% 1.0-0.2% 0.9-0.3% 0.7-0.1% 0.3-0.1% 1.3-0.2% Fineness: the fineness of the silica fume is less than 1 1/4m, and the average particle size is 0.1 0.3 1/4m, and the specific surface area is 20 - 28 m2/g. The fineness and specific surface area are about 80-100 times of cement and 50-70 times of fly ash. Maxtech Micro Silica supplies will be as per QCS 2014 (ASTM C1240): SiO2: >/= 92% LOI:
